events: implement package with memory & nats streams (#1942)

events/options.go

@@ -0,0 +1,140 @@
+package events
+
+import "time"
+
+// PublishOptions contains all the options which can be provided when publishing an event
+type PublishOptions struct {
+	// Metadata contains any keys which can be used to query the data, for example a customer id
+	Metadata map[string]string
+	// Payload contains any additonal data which is relevent to the event but does not need to be
+	// indexed such as structured data
+	Payload interface{}
+	// Timestamp to set for the event, if the timestamp is a zero value, the current time will be used
+	Timestamp time.Time
+}
+
+// PublishOption sets attributes on PublishOptions
+type PublishOption func(o *PublishOptions)
+
+// WithMetadata sets the Metadata field on PublishOptions
+func WithMetadata(md map[string]string) PublishOption {
+	return func(o *PublishOptions) {
+		o.Metadata = md
+	}
+}
+
+// WithPayload sets the payload field on PublishOptions
+func WithPayload(p interface{}) PublishOption {
+	return func(o *PublishOptions) {
+		o.Payload = p
+	}
+}
+
+// WithTimestamp sets the timestamp field on PublishOptions
+func WithTimestamp(t time.Time) PublishOption {
+	return func(o *PublishOptions) {
+		o.Timestamp = t
+	}
+}
+
+// SubscribeOptions contains all the options which can be provided when subscribing to a topic
+type SubscribeOptions struct {
+	// Queue is the name of the subscribers queue, if two subscribers have the same queue the message
+	// should only be published to one of them
+	Queue string
+	// Topic to subscribe to, if left blank the consumer will be subscribed to the firehouse topic which
+	// recieves all events
+	Topic string
+	// StartAtTime is the time from which the messages should be consumed from. If not provided then
+	// the messages will be consumed starting from the moment the Subscription starts.
+	StartAtTime time.Time
+}
+
+// SubscribeOption sets attributes on SubscribeOptions
+type SubscribeOption func(o *SubscribeOptions)
+
+// WithQueue sets the Queue fielf on SubscribeOptions to the value provided
+func WithQueue(q string) SubscribeOption {
+	return func(o *SubscribeOptions) {
+		o.Queue = q
+	}
+}
+
+// WithTopic sets the topic to subscribe to
+func WithTopic(t string) SubscribeOption {
+	return func(o *SubscribeOptions) {
+		o.Topic = t
+	}
+}
+
+// WithStartAtTime sets the StartAtTime field on SubscribeOptions to the value provided
+func WithStartAtTime(t time.Time) SubscribeOption {
+	return func(o *SubscribeOptions) {
+		o.StartAtTime = t
+	}
+}
+
+// WriteOptions contains all the options which can be provided when writing an event to a store
+type WriteOptions struct {
+	// TTL is the duration the event should be recorded for, a zero value TTL indicates the event should
+	// be stored indefinately
+	TTL time.Duration
+}
+
+// WriteOption sets attributes on WriteOptions
+type WriteOption func(o *WriteOptions)
+
+// WithTTL sets the TTL attribute on WriteOptions
+func WithTTL(d time.Duration) WriteOption {
+	return func(o *WriteOptions) {
+		o.TTL = d
+	}
+}
+
+// ReadOptions contains all the options which can be provided when reading events from a store
+type ReadOptions struct {
+	// Topic to read events from, if no topic is provided events from all topics will be returned
+	Topic string
+	// Query to filter the results using. The store will query the metadata provided when the event
+	// was written to the store
+	Query map[string]string
+	// Limit the number of results to return
+	Limit int
+	// Offset the results by this number, useful for paginated queries
+	Offset int
+}
+
+// ReadOption sets attributes on ReadOptions
+type ReadOption func(o *ReadOptions)
+
+// ReadTopic sets the topic attribute on ReadOptions
+func ReadTopic(t string) ReadOption {
+	return func(o *ReadOptions) {
+		o.Topic = t
+	}
+}
+
+// ReadFilter sets a key and value in the query
+func ReadFilter(key, value string) ReadOption {
+	return func(o *ReadOptions) {
+		if o.Query == nil {
+			o.Query = map[string]string{key: value}
+		} else {
+			o.Query[key] = value
+		}
+	}
+}
+
+// ReadLimit sets the limit attribute on ReadOptions
+func ReadLimit(l int) ReadOption {
+	return func(o *ReadOptions) {
+		o.Limit = 1
+	}
+}
+
+// ReadOffset sets the offset attribute on ReadOptions
+func ReadOffset(l int) ReadOption {
+	return func(o *ReadOptions) {
+		o.Offset = 1
+	}
+}